Methods :
3D-SIM images were examined for LG and MLG using three different excitation wavelengths (488, 568 and 647 nm). Our automated software identifies and quantifies (number, size and position) single granules in RPE flatmounts. The LG and MLG of an 88-year-old donor were examined for the macular region.

Results :
From 541 granules, 411 (76.0%) were identified as LG and 130 (24.0%) as MLG. LG and MLG were distributed towards the cell edge.

Conclusions :
Highly resolved 3D-images of LG as well as MLG are obtainable with SIM. LG and MLG can be differentiated and characterized regarding their number and position with a semi-automated analysis of the established SIM data. Quantitative characteristics of autofluorescent granules help to understand cellular processes within the RPE.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.